The subbaccalaureate educational attainment level --those who attended college but did not earn a bachelor's degree-- comprises 28% of American adults age 25 and older, or about 54 million people in the U.S. Surprisingly little is known about the health of adults in this major population group. A recent study by the PI and collaborators found a startling anomaly in the education gradient in health: adults at the subbaccalaureate level (especially college dropouts but also some recipients of associate's degrees) reported more health problems than high school graduates who never attended college. The gradient, which describes the monotonic positive association between schooling and health, has been understood to be universal across populations, health outcomes, and all levels of attainment. The fact that the gradient does not hold for 28% of the population may provide important clues about the mechanisms of the relationship between educational attainment and health. The long-term goal of the PI's research agenda is to understand how and why education and health are linked. The goal of this project is to compare the health of the subbaccalaureate group versus that of high school (HS) graduates who never attended college and college graduates, using three large, nationally-representative sources of data (the National Health Interview Survey 1997-2013, the National Health and Nutrition Examination Survey 1999-2012, and the National Longitudinal Survey of Youth 1979). In Aim 1, we will provide a detailed picture of the health patterns across multiple health dimensions, across major population groups, and across age, period, and birth cohorts. In Aim 2, we will explore how specific mediating and confounding mechanisms-employment, economic circumstances, health behaviors, childhood social conditions, cognitive/non- cognitive skills, and early health-explain the observed health patterns across the three education groups. This research is significant because: (1) Poorer-than-expected health in the large subbaccalaureate group must be addressed in health care policy and planning. (2) Explaining the anomalous patterns at the subbacca- laureate level can spur new theories to understand the relationship between schooling and health in general. This research is innovative because it seeks to challenge current research on the educational determinants of health by focusing on an anomaly in the gradient pattern. At the completion of this project, we will provide the first systematic assessment of the health of college dropouts and recipients of associate's degrees, as well as explore reasons why their additional schooling does not translate into a health advantage relative to HS graduates. We are thus proposing to answer an important, recently recognized issue of relatively poor health in the large subbaccalaureate group-an issue highly pertinent to NIH funding priorities, the U.S. health and educational policies, and the health of the American population-using methodologically and substantively innovative perspectives.